1DO2: Trigonal Crystal Form Of Heat Shock Locus U (Hslu) From Escherichia Coli

The degradation of cytoplasmic proteins is an ATP-dependent process. Substrates are targeted to a single soluble protease, the 26S proteasome, in eukaryotes and to a number of unrelated proteases in prokaryotes. A surprising link emerged with the discovery of the ATP-dependent protease HslVU (heat shock locus VU) in Escherichia coli. Its protease component HslV shares approximately 20% sequence similarity and a conserved fold with 20S proteasome beta-subunits. HslU is a member of the Hsp100 (Clp) family of ATPases. Here we report the crystal structures of free HslU and an 820,000 relative molecular mass complex of HslU and HslV-the first structure of a complete set of components of an ATP-dependent protease. HslV and HslU display sixfold symmetry, ruling out mechanisms of protease activation that require a symmetry mismatch between the two components. Instead, there is conformational flexibility and domain motion in HslU and a localized order-disorder transition in HslV. Individual subunits of HslU contain two globular domains in relative orientations that correlate with nucleotide bound and unbound states. They are surprisingly similar to their counterparts in N-ethylmaleimide-sensitive fusion protein, the prototype of an AAA-ATPase. A third, mostly alpha-helical domain in HslU mediates the contact with HslV and may be the structural equivalent of the amino-terminal domains in proteasomal AAA-ATPases.
PDB ID: 1DO2Download
MMDB ID: 12683
PDB Deposition Date: 1999/12/18
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 4  Å
Source Organism:
Similar Structures:
Biological Unit for 1DO2: hexameric; determined by author and by software (PISA,PQS)
Molecular Components in 1DO2
Label Count Molecule
Proteins (6 molecules)
Protein (Heat Shock Locus U)(Gene symbol: hslU)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB